The present invention relates to ignition leads used in spark-ignition, internal combustion engines. There are now common engines in which access to the spark plugs is severely restricted. In a typical example, each spark plug is seated at the bottom of a well defined by other components of the engine. This gives rise to some difficulty in the removal of and replacement of ignition leads connected with the spark plugs of some engines To overcome this problem, some new vehicles are fitted by the vehicle assembler with a substantially rigid carrier for each spark plug lead. The carrier includes a lower portion for gripping an elastomeric boot associated with the ignition lead and an upper portion adapted to serve as a handle. The handle facilitates manipulation of the boot, which contains a termination of the ignition lead, to engage the termination with and disengage the termination from a terminal of the spark plug.
The length of rigid carrier required differs from one engine to another. It is therefore necessary for a variety of rigid carriers to be manufactured and for an appropriate carrier for use in conjunction with a particular engine to be selected. In a case where a skilled person selects and installs the rigid carrier with a replacement ignition lead, the known carriers may be satisfactory. However, in cases where the person who selects the carrier is unskilled, the existence of a variety of carriers, differing in respect of their lengths, is likely to lead to difficulties for example the selection and purchase of a rigid carrier which is unsuitable for the particular engine with which the replacement carrier and ignition lead are to be used.